Electrophotographic copying paper containing poly-n-vinyl-3-azo carbazole

ABSTRACT

POLY-N-VINYL-3-AZO CARBAZOLE WHICH IS OBTAINED BY THE COUPLING BETWEEN POLY-N-VINYL CARBAZOLE AND A DIAZO COMPOUND SELECTED AS DESIRED FROM VARIOUS DIAZO COMPOUNDS IS EXTREMELY SUITABLE AS A PHOTOCONDUCTIVE MATERIAL FOR USE IN ELECTROPHOTOGRAPHIC COPYING PAPERS. AN ELECTROPHOTOGRAPHIC COPYING PAPER WHICH IS PREPARED BY COATING THIS POLY-N-VINYL-3-AZO CARBAZOLE ON A SUPPORT PAPER SHEET WHICH TRANSMITS ULTRAVIOLET RAYS THERETHROUGH CAN BE UTILIZED AS THE MATERIAL FOR PREPARING A SECOND ORIGINAL FOR THE COPYING PROCESS WHICH USES DIAZOTYPE COPYING PAPERS.

United States Patent fice 3,583,869 ELECTROPHOTOGRAPHIC COPYING PAPERCON- TAINTNG POLY-N-VINYL-3-AZO CARBAZOLE Kazuo Tubuko, Tokyo, TetsuoTanaka, Kasukabe-shi, and Nario Yamagnchi, Tokyo, Japan, assignors toKabushiki Kaisha Ricoll, Tokyo, Japan No Drawing. Filed Mar. 18, 1968,Ser. No. 714,092 Claims priority, application Japan, Mar. 24, 1967, 42/18,441 Int. Cl. G03g /00 US. Cl. 96-15 3 Claims ABSTRACT OF THEDISCLOSURE BACKGROUND OF THE INVENTION (a) Field of the invention Thepresent invention is concerned with an electrophotographic copying paperwhich is provided, on one surface thereof, with a light-sensitive layerwhich contains an organic photoconductive material. More particularly,the present invention is related to an electrophotographic copying paperwhich is provided, on one surface thereof, with a light-sensitive layerwhich contains poly-N-vinyl-3-azo carbazole as the photoconductivesubstance.

(b) Description of the prior art As the photoconductive substances foruse in the conventional electrophotographic copying papers, thoseinorganic substances such as zinc oxide, selenium and sulfur; and thoseorganic substances such as anthracene, anthraquinone, oxadiazol andpoly-N-vinyl carbazole which is a polymer having a high molecularweight, are known. A light-sensitive layer which is formed on thesupport of a copying paper andwhich is prepared with such an organicsubstance as described above to serve as the photoconductive substanceis, in general, superior in the ability of transmitting ultraviolet raysas compared with the light-sensitive layer of a copying paper which isformed with an inorganic substance to serve as the photoconductivesubstance. Therefore, an electrophotographic copying paper which isobtained .by the employment of anorganic photoconductive substance is ofan advantage that it can be used also as the copying paper which isintended for the preparation of a secondary original adapted for thecopying process which utilizes diazotype copying papers. Those organicphotoconductive substances which have been used in the past, however,are poor in their sensitiveness to light. In addition, theseconventional organic photoconductive substances have a furtherinconvenience that it is difficult to uniformly disperse them in amixture which is prepared for use in the coating of the supports.

SUMMARY OF THE INVENTION It is, therefore, the object of the presentinvention to provide an electrophotographic copying paper having, on onesurface thereof, a light-sensitive layer which con- 3,583,869 PatentedJune 8, 1971 tains such a polymer as is expressed by the followingchemical formula to serve as the photoconductive substance:

wherein -R represents a residual radical of a diazo compound.

Some of these residual radicals of the diazo compounds which areexpressed by the aforesaid chemical formula will be shown as follows:

wherein R and R are selected from the group consisting of H, -OCH OC H-OC H and -OC H a f Q wherein R and R are selected from the groupconsisting of H, -CH -OCH -OC H 0C H and OC4H9.

I ia

wherein R and R are selected from the group consisting of H, -OCH3,-'OCZH5, '-'OC3H7 and -OC4Hg- I IIa R and R are selected from the groupconsisting of H,

-OCH OC H and R is selected from the group consisting of H and wherein:

wherein R and R are selected from the group consisting of -H,

OCH3, OC2H5, -OC3H7 and -OC4'H9;

R is selected from the group consisting of-CH and C2H5; and

R is selected from the group consisting of --OH C H and -4C2H5.

j in the presence of, for example, potassium hydroxide.

The diazo compounds which are suited for the object and of the presentinvention are prepared by using the follow- OH ing substances including:1|

2-methyl-4-ethyl-aniline 4-methyl-benzylaniline2,5-diethoxy-4'-methoxy-benzoylani1ine 4-morpholinobenzene M 2,5-dimethoxy-4-toluylmercaptobenzene 0 Triphenylamine 1,3-bis[naphthoquinone 1 )-su1fonyloxy (5 ]-hydroxy 5 benzene and I 4,4'-bis[naphthoquinone 1)-sulfony1aniline].

Furthermore, a photoconductive substance of the present invention can beprepared also by causing a reaction S02E15 between a compound expressedby any one of the following chemical formulas and poly-N-vinylcarbazole:

wherein R is selected from the group consisting of (1H3 it 20 N \N -o o-N S 02R and wherein R is selected from the group consisting of wherein Ris selected from the group consisting of (ID @U wherein R is selectedfrom the group consisting of wherein R is selected from the groupconsisting of 11 on +112 Q e CH2 CH2 and i t 03 03) ll. 1%.

wherein R is selected from the group consisting of l ilnn-o o-HN-@ s0311 The poly-N-vinyl-3-azo carbazole which is employed in the presentinvention is, in itself, of a quite superior photoconducting property,and therefore, it can be directly used as the material for the formationof a light-sensitive layer by applying the same onto one surface of asupport by relying on an appropriate coating technique such as spraying,brushing or coating by means of rollers. Or, alternatively, said azocarbazole may be treated with alcohol to be refined, and then therefined substance may be dissolved in an organic solvent, and theresulting solution may be applied onto one surface of a support to forma light-sensitive layer thereon.

Also, in order to further enhance the sensitivity to light of thelight-sensitive layer, it is desirable to use a sensitizing dyestuffand/ or an assistant sensitizer jointly with the aforesaidphotoconductive substance. As the sensitizing dyestuffs, the employmentof such substance as Brilliant Green, Victoria Blue B, Methyl Violet,Crystal Violet, Acid Violet, Rhodamine B Extra, Sulforhodamine B,Fluorescein, Methylene Blue, Acridine Yellow and Acridine Orange, issuitable.

As the assistant sensitizer, the employment of such acids as aceticacid, monochloro acetic acid and dichloro acetic acid, or their salts;or metal halides such as antimony pentachloride and stannous chloride;or quinones such as p-benzoquinone and p-chloranil, is suitable.

In case the light-sensitive layer of the electrophotographic copyingpaper of the present invention is impressed with a positive or anegative charge by means of corona discharge, the charged copying paperwill exhibit sensitivity to light having a wavelength ranging from 3600A. to 7000 A. Therefore, a very clear copied image will be obtained byexposing the charged copying paper to light for an extremely shortperiod of time, utilizing a tungsten lamp as the light source. It is tobe noted, however, that a light-sensitive layer which has a much bettersensitivity to light is obtained by including the aforesaid sensitizingdyestuff and/or an assistant sensitizer at the time said light-sensitivelayer is formed. According to the present invention, the support may bemade with a film or a sheet material made of a material includingaluminium, zinc or copper; paper; cellulose esters such as celluloseacetate and butyl cellulose; polyolefins such as polyethylene andpolypropylene; polyvinyl compounds such as polystyrol, polyvinylchloride and polyvinlidene chloride; polyacryl compounds such aspolyacrylonitrile and polymethacrylate; polyesters such aspolyterephthalic acid and glycol esters; and plastics such as polyamidesand polyurethanes. These films and sheet materials other than the metalsheets are used after they have been given an electroconductingtreatment according to the known process. In the event that paper sheetsare used as the supports, it is preferred to treat these paper sheets,prior to using the paper sheets as the supports, with, for example, anaqueous solution and HOaS

of methyl cellulose or polyvinyl alcohol; or with an acetone or methylethyl ketone solution of a copolymer of methyl acrylate ester andacrylonitrile; or with an alcohol solution of a polyamide.

As has been stated, the present invention contemplates the provision ofa novel electrophotographic copying paper having a light-sensitive layerformed on one surface of a support, said light-sensitive layer beingprepared essentially with a photoconductive substance consisting of apolyvinyl azo compound. This electrophotographic copying paper obtainedaccording to the present invention is of a number of advantages andconveniences such that the copying paper can be manufactured easily;that it is free from the fear of a reduction in its sensitivity to lightduring the storage lasting for an extended period of time, meaning thatthis copying paper has a very good shelf-life; and also that copyingpaper which is manufactured by the use of a transparent support can beutilized as a secondary original which is suitable for diazotype copyingpapers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 To gr. of 5%monochloro benzene solution of poly-N-vinyl carbazole was added 2 cc. of5% methanol solution of a double salt ofp-diazo-2,5-dimethoxy-l-ptoluylmercaptobenzene and zinc chloride. Afterstirring the resulting mixed solution, the latter was added with 0.2 cc.of 5% methanol solution of potassium hydroxide. This mixed liquid wasallowed for reaction therebetween at a temperature ranging from 45 C. to50 C. for 10 minutes, while stirring the same. Thus, a solution for usein the formation of a light-sensitive layer was prepared. This solutionwas applied onto one surface of a tracing paper which had been priorlygiven an electroconducting treatment, and the same was dried, with aresult that an electrophotographic copying paper was obtained. Afterimparting the light-sensitive layer of the electrophotographic copyingpaper thus obtained an electrostatic sensitivity to light by impressingsaid light-sensitive layer with a negative charge by corona discharge,the charged light-sensitive layer of the copying paper was exposed, for2.5 seconds through a positive original placed thereon, to light comingfrom a light source which was a tungsten lamp of 100 watts which wasdisposed at a distance of 30 cm. from said light-sensitive layer. Theexposed copying paper was developed according to a known wet typedevelopment method. As a result, a very clear copied image was obtained.This copied image was found to be a faithful reproduction of theoriginal image. It was also noted that this copy was quite suitable foruse as the secondary original for diazotype copying papers.

Example 2 To 100 gr. of 5% monochloro benzene solution of poly-N-vinylcarbazole was added 3 cc. of 5% methanol solution of a double salt ofp-diazo-l-morpholino benzene and zinc chloride. After stirring thismixed solution, the latter was added with 0.2 cc. of 5% methanolsolution of potassium hydroxide. After allowing the resulting mixedliquid to react therebetween at a temperature ranging from 45 C. to 50C. for 10 minutes While stirring the liquid, the latter was addedfurther with 0.5 cc. of 5% methanol solution of Methylene Blue FZ andalso with 1.5 cc. of 10% methanol solution of aluminum nitrate, followedby a thorough stirring. Thus, a solution for use in the formation of alight-sensitive layer was prepared. This solution was applied onto onesurface of a cellulose acetate film which had been priorly given anelectroconducting treatment, and the same was dried, with a result thatan electrophotographic copying paper was obtained. For comparison, acontrol electrophotographic copying paper was manufactured by firstpreparing a solution for the formation of a light-sensitive layer byadding the methanol solutions of Methylene Blue FZ and aluminiumnitrate, respectively, to poly-N-vinyl carbazole, and then applying thissolution onto one surface of a support similar to the one used in thisinstant example, and then drying the same. These two copying papers werethen processed in the same way as that described in Example 1, and thus,copied images were produced. The sensitivities of these two copyingpapers Were compared based on the effects of the two copies obtained. Itwas found that the copying paper of the present invention had alight-sensitivity which was 1.5 times higher than that of the controlcopying paper.

Example 3 To 100 gr. of monochloro benzene solution of poly- N-vinylcarbazole was added 4 cc. of 5% methanol solution ofp-diazo-diphenylaniline. After stirring the resulting mixture, thelatter was added with 0.2 cc. of 5% methanol solution of potassiumhydroxide. While stirring the mixed liquid, the latter was allowed forreaction at a temperature ranging from 45 C. to 50 C. for 15 minutes.Thereafter, the resulting liquid was added further with 0.5 cc. of 5%methanol solution of Methylene Blue FZ and also with 1.5 cc. of methanolsolution of aluminium nitrate, followed by a thorough stirring. Thus, asolution for use in the formation of a lightsensitive layer Wasprepared. This solution was applied onto one surface of a tracing paperhaving priorly been given an electroconducting treatment, and the samewas dried, with a result that an electrophotographic copying paper wasobtained. This copying paper was then subjected to a process in a mannersimilar to that described in Example 1 to form a copied image. Thecopied image thus obtained was noted to be a very clear one. Theexposure to light in this example used a tungsten lamp of 100 watts asthe light source which was disposed at a distance of 100 cm. from thelight-sensitive layer and the exposure lasted for 3 seconds.

wherein R represents a residual radical of a diazo. compound. I

,2. An electrophotographic.copying paper according to claim 1, whereinsaid support is made with a material having a-property of transmittingultraviolet rays. 3; An electrophotographic copying paper according toclaim 1, whereinsaid light-sensitive layer further contains at least oneof the agents selected from the group of sensitizing dyestuffs andassistant sensitizers.

References Cited UNITED STATES PATENTS 3,113,022 12/1963 Cassiers et al.961 3,312,673 4/1967 Hewett Q 26080.3 1/1969 Inami et al. 961.6

GEOR GE F. LESMES, Primary Examiner M. B. WITIENBERG, Assistant Examinerv US. Cl. X.R. 260-883, 152, 164; 252 s01

